LAUSR

Abstract Fish are a primary source of long‐chain omega‐3 fatty acids, which may help delay cognitive aging. We pooled participants from the French Three‐City study and 4 US cohorts (Nurses’ Health Study, Women's Health Study, Chicago Health and Aging Project, and Rush Memory and Aging Project) for whom diet and cognitive data were available (n = 23,688 white persons, aged ≥65 years, 88% female, baseline year range of 1992‐1999, and median follow‐up range of 3.9‐9.1 years) to investigate the relationship of fish intake to cognitive decline and examine interactions with genes related to Alzheimer disease. We estimated cohort‐specific associations between fish and change in composite scores of global cognition and episodic memory using linear mixed models, and we pooled results using inverse‐variance weighted meta‐analysis. In multivariate analyses, higher fish intake was associated with slower decline in both global cognition and memory (P for trend ≤ 0.031). Consuming ≥4 servings/week versus <1 serving/week of fish was associated with a lower rate of memory decline: 0.018 (95% confidence interval: 0.004, 0.032) standard units, an effect estimate equivalent to that found for 4 years of age. For global cognition, no comparisons of higher versus low fish intake reached statistical significance. In this meta‐analysis, higher fish intake was associated with a lower rate of memory decline. We found no evidence of effect modification by genes associated with Alzheimer disease.